The present invention relates generally to microelectronic devices and more particularly to an electrostatically shielded microelectronic devices based on field emitter technologies.
An easy-to-build flat panel display has been considered as the "Holy Grail" in the area of electronics. Numerous researchers have been trying to invent such a display.
One essential element of such a display is transistors or microelectronic devices to control the field emitters. Various transistors have been proposed and implemented, for example, using thin-film techniques to fabricate bipolar transistors and field effect transistors on semiconductor substrates.
Unfortunately, most prior art transistor techniques are usually not compatible with the technologies to fabricate the field emitters. A field emitter usually has a very sharp tip, at zero or negative voltage, positioned in close proximity to a gate at a different voltage to emit electrons. Such structures are quite different to the prior art structures of bipolar and field effect transistors. Thus, field emitters and transistors have to be built by different processes, significantly increasing the complexities in making a flat panel display.
One prior art method tries to use the field emitter approach to build a transistor. That device has an emitter emitting electrons, and a collector at a positive voltage to collect the emitted electrons. However, the device is not electrostatically shielded and is very susceptible to influences from the environment. Operation of field emission depends critically on the trajectories of the electrons. These trajectories, in turn, are influenced by the shapes and electric potentials of their surrounding structures. For example, if the device is positioned under a screen with a positive voltage, as in a flat panel display, the electrons initially going to the collector would be attracted towards the screen, significantly degrading the performance of the device.
It should be apparent from the foregoing that there is still a need for a microelectronic device that is based on similar technologies as field emitters to function in areas, such as flat panel displays.